Valve-snap action



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Patented July. 12, 1927.

UNITED STATES FRED G. SCHWEISTHAL, OF CHICAGO,

SPEEDOMETIEBl CORPORATION, 0F CHICAGO, ILLINOIS,

GIN'IA.

ILLIOIS, ASSIGNOB, TO STEWART-'WARNER .A CORPORATION OF 'VIR-jVALVE-SNAP ACTION.

Application led November 21, 1924. Serial No. 751,205.

10 v In the drawings:

Figure 1 is a vertical axial section of a vacuum fuel feed tank havingthe valve operating connections from the float embodying this invention.

Figure 2 is a partial view, similar to Fig. 1, of the operatlng parts.of the device, the same being shown in a dierent position.

Figure 3 is a detail section at the lin'e, 3 3, on Figure .1, showingthe valve snap 20 action in plan view.

Figure 4 is a. sectional view similar to Fig. 2, showing modified formof the invention.

Figure 5 is a section similar to Figure 2 26 showing anothermodiiication.

In the structure shown in the drawln'gs 1 is the main or outer tankmember; 2 is the inner tank member or vacuum chamber; 3'is the liquidinlet to the vacuum chamber; 4 is the outlet valve from the vacuumchamber -to the main` chamber; 5 is the suction connection to the vacuumchamber; 6 is the air connection to the vacuum chamber; 7 is the suctioncontrolling valve; 8 is the air controlling valve. The snap action foroperating the valves from the iioat, A, comprises the customary levers.9 and 10, having fulcrum-in-common'at 11, and their remote endsconnected by the snap springs,

4 12, the lever, 9, being connected by a link,

. 13, with the float-connected lever, 14, which has a fulcrum at 15,ixed with respect to the vacuum chamber wall, and which is pivotallconnected at 16, with the float stem, l; The valves, 7 and 8, have thecustomary loose pivotal connection with the lever, 10, adapting them tobe operated by the snap action and to accommodate themselves to theirseats by the freedom of their connection with the lever, 10, asmentioned. It will be understood that thelevers, 9 and 10, havev theusual cro-ss bars, 9 and 10, at their remote ends forattaching theopposite ends of the springs, 12, which are duplicated in the wellunderstood manner and for the well understood reason for permitting thesprings to pass the fulcrum of the levers in the snap action.

In the well understood operation of this familiar valve snap action,when the float, rising with the rising level of the liquid in the vacuumchamber, carries the sprin past the fulcrum line, causing 'theupwarssnap to occur, the lever, 10, which engages between the stops, 8,8", of the stem of the valve, 8, is snapped up against the upper stop,8*, and operates by virtue only of the stress of the spring and with theforce due only to the tension to which the spring has been subjected inbeing carried past the fulcrum, 11, for breaking the air valve, 8, awayfrom its seat against the suction tending to holdit seated. In cases ofextreme suction, the reaction of the spring may not be suicient toovercome the suction hold on the valve. AIn the construction shown,however, the extension, 14", of the lever, 14, beyond its pivotalconnection with the float stem being in the vertical plane of thrust ofthe valve, 8, and extending under the lowe'r end of the valve stem andderiving from the upward .movement of the float a vertical movement ofabout twice that of the float, is caused to strike the lower end of thestem of the valve, 8, a quick blow when the snap action occurs, thusovercoming the suction hold on the valve and insuring its opening whenthe snap action occurs under circumstances which might prevent itsopening in the absence of said lever extension.

While the extension, 14, of the lever, 14, is particularly effectivebecause its extended portion travels farther and faster than the liioatitself, this multiplication of movement is not essential to the result.Figure 4 shows a slightly modified construction in which the lever, 14X,corres ending to lever, 14, does not extend beyon its pivotal connection with the ioat, lA, but instead, the float carries a boss, 18,and the stem of the valve, 8, is extended downward as seen at 8 forencounter with the boss, 18, as the iioat approaches the upper limit ofits movement. The snap action of course accelerates this fin al portionof the iioat movement and causes it to strike a direct blow upon theextension,l 8c, for unseating the valve, 8. If

desired instead of extending the valve stem downward an auxiliary stern,19 may be mounted on the float, A, in a supporting boss, 20, as shown inFigure 5, this stem, 19, being aligned with the stem of the valve, 8, soas to encounter the lower head or stop, 8", and dislodge the valve fromits seat as the float is snapped upward at the limit of its travel.

I claim l,

1. In a device for the purpose indicated in combination with a chamberhaving .liquid inlet and outlet and having a fluid pressure connectionat 'the upper part, a valve controlling said fluid pressure connection;a float adapted to move with the change of level of the liquid; a snapaction connection between the valve and the float comprising a pivotedlever pivotally connected with the float and extended from the floatpivot in a plane for encounter of its extension with a valve-connectedpart in the snap movement whereby the snap action causes the leverextension to strike a blow for displao ing the valve from its seat.

2. In a device for the purpose indicated, in combination with a chamberhaving liquid inlet andoutlet and having a suction connection forproducing partial vacuum above. the liquid and an atmosphere connec-`tion for defeating such partial vacuum, a valve controlling the airconnection; a float adapted to move with the change of level ot' the,liquid, a snap action connect-ion between the valve and the float.comprising a lever pivotally connected with the float and extending afree end portion from said pivotal connection in a plane for encounterof said extension in the snap movement with a valve-connected part,whereb7 the lever extension is caused to strike a blow for breaking thesuction hold on the air valve in the movement of the float due to therise of the liquid level.

3. In a device for the purpose indicated, in combination with a chamberhaving liq uid inlet and outlet and having a fluid pressure connectionat the upper part, a valve controlling said fluid pressure connection: afloat adapted to move with the change of level of the liquid; asnap-over device con nected with the float and means connected withthesnap-over device for striking the Leemans valve in the direction fordisplacing it from its seat, having in the snap an extended range ofmovement for acquiring momentum before it encounters the valve.

Y 4. In a device for the purpose indicated, in combination with achamber having liquid inlet and outlet and having a fluid pressureconnection at the upper part, a valve controlling said fluid pressureconnection, a float adapted to move with change of level of the liquid,a snap action connection between the valve and the float including a lever pivotally connected to the float and having a free end portionfarther from the lever ulcrum than said pivotal connection, whereby saidfree end has a wider range of travel than the float; said end portionmoving in a plane for encounter with a valveconnected art in the snapmovement for striking a lilow tovdisplace the valve from its seat.

5. In a device for the purpose indicated, in combination with a chamberhaving liquid inlet and outlet and having a fluid pressure connection atthe upper part, a valve controlling said fluid pressure connection, afloat adapted to move with the change ot' level of the liquid, asnap-over device connected with the float and with the valve designed toaccelerate the movement of the float as it approaches its limit oftravel and means carried by the float for direct en- .counter with avalve-connected part in said accelerated movement for displacing thevalve from its seat.

6. In a device Vfor the purpose indicated, in combination with a chamberhaving liquid inlet and outlet and having a fluid pressure connection atthe upper part, a valve controlling said fluid pressure connection, alioat adapted to move with the change of level of the liquid, a.snap-over device connected with the float and with the valve designed'to accelerate the movement of the float as it approaches its limit oftravel and means positively connected to the float in position fordirect encounter with a valve connected part for striking a blow todisplace the valve.

In testimony whereof, I have hereunto set my hand this 19th day ofNovember, 1924. FRED G. SCHlVEISTHAL.

